Agitator for rotary filters



Jan; 16 1951 Filed March ll, 1948 J. w. LITTLE 2,538,110

AGITA'I'OR FOR ROTARY FILTERS 2 Sheets-Sheet l 44 INVENTOR. 4''] 4/0/10 N L/ff/ F. BY 4122 .54

Jan. 16 1951 Filed March 11, 1948 J. W. LITTLE ACITATOR FOR ROTARY FILTERS 2 Sheets-Sheet 2 INVENTOR- c/ofin W. luff/e Patented Jan. 16, 1951 AGITATOR FOR ROTARY FILTERS John W. Little, Birmingham, Ala., assignor to Goslin-Birmingham Manufacturing Company, Inc., a corporation of Alabama Application March 11, 1948, Serial No. 14,187

3 Claims.

and more particularly to an improved support and drive for the agitator disposed beneath the filter drum in the tank. 1

As is known in the art to which my invention relates, it is necessary when filtering most substances with a rotary filter to continuously agitate the liquid in the filter tank. The apparatus for accomplishing this is in the form of a series of bars or vanes, cross connected at either end, and mounted for reciprocation between the lower surface of the drum and the bottom of the tank. It has, heretofore, been proposed to suspend the agitator assembly for reciprocatory movement either from the main trunnion of the filter or from bearings mounted on the ends of the drum support. In the latter types of construction with which I am familiar, the points of suspension of the agitator have been considerably above the axis of the drum with the result that the radius of the tank bottom has had to be larger than actually needed for filtering purposes. That is to say, due to the fact that the points of suspension of the agitator assembly have heretofore been higher than necessary, the tanks employed with such filters haveof necessity been larger than were necessary to hold the required amount of liquid being filtered. In prior apparatus of the latter type, the bearings for suspending the agitator assembly have been provided by machining a surface on the main drum bearings and securing the bearings for the agitatorsto the surfaces thus prepared. Unless misalignment of the agitator is to be prevented, great accuracy in machining of these surfaces must be obtained, and such construction is expensive in machine shop time and labor. s

It is a prime object of my invention, therefore, to overcome the above difficulties in filters of the type in which it is desired to support the agitator from above the drum bearings, thereby to provide a filter of the character designated in which the agitator assembly is mounted for reciprocation on antifriction bearings supportedin housings formed integrally with the main supporting bearings of the drum, whereby the center of the agitator bearing is as near the axis of the drum as possible. o

Another object is to form the housings for the agitator bearings integrally with the housing for the drum bearings whereby the fomer may beline bored, thus to assure perfect alignment of both ends of the agitator with a minimum of machine shop time and difliculty. I q i p r A further object is to support each end of the agitator on a short length of shaft, rotatably supported in a pair of sealed antifriction bearings disposed in the housings, the bearings being displaced axially along the supporting shafts thus to support each shaft at two spaced apart points.

Another object is to provide apparatus of the character designated in which the bottom of the tank is formed on a radius struck from the center of the agitator support bearings, and continues upwardly on one side along the same radius, whereby the agitator may be rocked completely out of the tank without removing the drum, thus to facilitate repair of the same.

A still further object is to provide drive means for reciprocating the agitator assembly andconnected thereto at each end, such drive means sin-- bodying a shaft having cranks on either end and a driving connection adjacent its longitudinal center, whereby torsional deflection in the shaft is reflected equally at each end of the agitator assembly, thus to move both ends of the agitator evenly and prevent warping of the assembly.

Apparatus embodying the features of my invention is illustrated in the accompanying drawings forming a part of this application in which:

Fig. l is a side elevationalview, partly broken away, of a filter embodying the features of my invention;

Fig. 2 is an end view thereof, partly broken away and in section, taken at the valve end of the filter;

Fig. 3 is a longitudinal sectional view, the drum being partly in elevation and partly in section; and,

Fig. 4 is an enlarged detail view of one of the agitator support bearings.

Referring now to the drawings for a better understanding of my invention, I have illustrated the same in association with a well known type of rotary filter. The filter comprises a tank In which is standard and well known except for the differences hereinafter pointed out, and em bodies the outer frame members I l and I2, preferably in the form of channels with their flanges outturned. The entire apparatus is supported. from the frame members ii and 12 by means of suitable pillars [3. Suitable piping connections for the liquid to be filtered are provided on the tank, and the same may be provided with a drain Mounted in sleeve bearings It and ii at the valve and drive ends, respectively, of the filter is a rotatable filtering drum [8. The drum is compartmented in the usual manner, and, the valve end 19 has associated therewith suitable vacuum and pressure means for the well known purposes. The drum may be driven by means of a gear 2| and a worm 22, the latter being rotated by suitable means, not shown.

The bearings l6 and ii are of the cast type and embody the lower halves 23 and 24, respectively, and the caps or upper halves 26 and 2?, respectively. The lower half of each bearing is bolted to the frame members H or I2 by means of nuts and bolts 28 and 29, and the caps are held to the lower halves by means of nuts and bolts 3! and 32.

Formed integrally with the bearing caps 26 and 2?, at the tops thereof, are a pair of housings 33 and 34. Each of the housings 33 and 35 are identical, and the description of one will suffice for both. As shown more clearly in Fig. 4 of the drawing, each of the housings is bored as indicated at 35 and counterbored at each end as to provide axially displaced recesses 3'! for receiving the outer races 38 of a pair of antifriction bearings 35. Each of the bearings has an inner race 35, and suitable seals 4i are provided to completely seal the bearing against the ingress of foreign matter and the egress of lubricant. The housings are provided with vertical lubricant passages l2, and screwed into the upper end thereof is a lubricant fitting 43. The housings 33 and 3B are substantially as long as the width of the hearing caps, and the antifriction bearings 35 therein are spaced a considerable distance apart. The longitudinal axis of the housings preferably lie in a vertical plane passing through the longitudinal axis of their associated main bearing.

Fitting within the inner races 39 of each of the bearings is a short length of shaft 14. As shown clearly in the drawings, the shafts 35 project from the housings 33 and 3d inwardly toward the drum. The inner races 39 are made fast to the shafts 44 by means of set screws 46.

On the projecting inner ends of the shafts 44 I mount the upper end ll of a pair of agitator support members 18, each of which is in the form of the letter C. The ends cl are secured to the shafts it by means of keys ii) whereby members 48, shafts 44, and the inner races 35 of the bearings 35 rotate together.

On the lower ends of each of the members :3 is a plate 52, secured thereto by means of a plurality of nuts and bolts 53. The lower edges of each of the plates 52 are notched out to provide recesses M for receiving a plurality of agitator bars in the form of inverted angles 56. The angles 56 are secured in the notches 54 by welding or otherwise, and as shown clearly in Fig. 1 of the drawing, pass beneath the drum l8 and are substantially coextensive in length therewith. It will be apparent, therefore, that the entire agitator assembly comprising the members 38, the plates 52, and the angles 56 is supported at each end on the shafts M and is free to rock or oscillate in the bottom of the tank Hi. The C shape of members 18 permits the lower ends 5! thereof to rock past the vertical axis of the drum without contacting the axially disposed supporting, valve, and drive mechanism thereof.

Mounted on one side of the tank iil, adjacent each end thereof, are bearings 57 and 58. A shaft 59 is rotatably supported in the end bearings 51 and 58 and a center bearing and carries cranks GI and 62 adjacent each end. Rotatably mounted on the outer ends of the cranks 6! and 62 are a pair of links 53 and 64. The links extend upwardly and are pivotally connected at their upper ends as at 66 and 6? to one end of a pair of arms 68 and 69. The other ends of the arms 68 and 69 are secured to the plates 52 by means of a plurality of bolts '1 i.

The shaft 59 has a sprocket i2 secured thereto adjacent its longitudinal center. A sprocket chain 73 passes around the sprocket l2, and thence over a sprocket '14 mounted on the output shaft 16 of an electric gear motor ii. The chains and sprockets may be enclosed in a guard '55.

Referring more particularly to Fig. 2 of the drawing, it will be seen that the bottom its of the tank Hi is struck on a radius from the axial center line of the shafts M. The bottom iiia continues upwardly on the same radius on that side of the tank adjacent shaft 5:), as indicated by the numeral 18. With the bottom thus constructed, the entire agitator assembly comprising the members &8 and the angles 56 may be removed from the tank simply by disconnecting the links 63 and 64 and pulling upwardly on the arm 68 and 69. This construction of the tank and agitator affords means for making the agitator assembly easily accessible for repairs or cleaning without the necessity of removing the very heavy drum !8 and mechanism associated therewith. This feature is particularly important in that repairs to the agitator assembly are frequently necessary due to the corrosive and abrasive nature of the materials being filtered. Since the center line of the shafts :34 are closed to the center line of the drum, the radius of the tank bottom is considerably shortened over that found in prior apparatus, and the tank of my filter is smaller than tanks employed with drums of comparable size in prior apparatus.

From the foregoing the method of constructing my improved agitator assembly will be readily understood. It will be noted that the pair of hearings in each of the housings and 34 are spaced apart substantially the length of the housings, thus to support the shafts M at a pair of axially displaced points. This arrangement decreases the stresses on the shafts it, permits the use of small bearings, and adds rigidity to the entire agitator assembly.

It is to be further noted that the caps 26 and 21 of the main drum bearings with which the housings 33 and 34 are formed integrally may be easily set up on the proper machine tools for line boring the housings 33 and 34. Accuracy in alignment of the shafts 44 and their bearings is thus obtained with a minimum of time and effort. Due to the length of the agitator assembly, slight misalignment of the shafts ii would cause warping of the entire agitator assembly when it is reciprocated back and forth since the assembly is not rigid. By forming the housings 33 and 34 integrally with the caps 26 and 2? and line boring the housings, I have found that misalignment is eliminated.

By mounting the sprocket '22 in the longitudinal center of the shaft 58, torsional deflections of the ends thereof are transmitted through. the cranks equally to the members 48 supporting each end of the agitator assembly. Warping of the assembly due to uneven driving of the ends thereof is thus materially reduced.

From the foregoing it will be apparent that I have devised an improved agitator support and drive mechanism for use with rotary filters which is simple of construction, in which the points of suspension therefor are close to the axial cen ter of the drum, in which the tank is so constructed and arranged that the entire agitator assembly may be withdrawn for repairs without moving the drum, and in which the tank bottom is struck on a radius of as nearly the same length as the radius of the drum as is possible when supporting the agitator from the tops of the drum bearings.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In a filter embodying a tank and a filtering drum, main bearings at each end of the drum in which the drum is mounted for rotation, housings at the top of each of the main bearings disposed adjacent the ends of the drum and inwardly of the outer periphery thereof, said housings being bored to provide integrally disposed axially displaced recesses at each end thereof, anti-friction bearings in the recesses of each housing, a shaft in the bearings of each housing projecting from the housing toward the ends of the drum, an agitator assembly supported at each end from said shafts, drive means for the agitator assembly comprising a shaft mounted for rotation on a side of the tank, cranks on the ends of the shaft, links operatively connecting the cranks with the ends of the agitator assembly, and means to rotate the shaft.

2. Apparatus as defined in claim 1 in which the means to rotate the drive shaft for the agitator assembly comprises a driving connection disposed at a point adjacent its longitudinal center.

3. In a filter embodying a filtering drum, main bearings rotatably supporting the drum at its ends, a housing at the top of each bearing formed integrally therewith, other bearings in each of the housings vertically aligned with the associated main bearing, a stub-shaft rotatably mounted in each of the said other bearings and projecting from the housings toward the ends of the drum, an agitator assembly supported at each end from the shafts, a tank in which the lower portion of the drum projects, the bottom of said tank being struck on a radius from the center of the bearing housings, said bottom continuing upwardly on the same radius and forming'a side of the tank, arms projecting outwardly and upwardly from each end of the agitator assembly over the curved side of the tank, links removably connected to the outer ends of each of said arms,

and means connected to said links for moving the same up and down thereby to reciprocate the agitator assembly.

JOHN W. LITTLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,659,699 Oliver Feb. 21, 1928 1,858,900 Moore May 17, 1932 2,109,766 Bullard Mar. 1, 1938 2,151,944 Stevens Mar. 28, 1939 2,312,620 Bowman Mar. 2, 1943 FOREIGN PATENTS Number Country Date 342,052 Germany Oct. 15, 1921 

